The objectives of this Program-Project for the coming year continue to be the elucidation of the molecular mechanisms of a number of genetic phenomena in mammalian systems. These include; (1) The study of transformation and latency in mammalian cells by herpes simplex virus by genetic and biochemical means; (2) The genetic and biochemical mechanisms by which hormones regulate specific gene expression in rat hepatoma cells in tissue culture; (3) The study of abnormalities of hemoglobin structure and thalassemia to understand regulation of hemoglobin biosynthesis and function; (4) Using the mammalian carbonic anhydrase isozymes as a model system, the selective factors which have shaped the evolution of enzymes and these mechanisms that are involved in the control of their expression at the cellular level will be analyzed; and (5) The exploration of the effects of mutations in the t-region and deletion at the color locus in development, focusing especially on male gametogenesis in mice.